A typical liquid crystal display generally includes a liquid crystal panel, and a backlight module. The backlight module includes a light source, a reflection cover, and a light guide plate combined to provide a uniform plane light for illuminating the liquid crystal panel.
Referring to FIG. 7, this shows an exploded view of a conventional backlight module 1 of a liquid crystal display. The backlight module 1 includes a frame 11, an illumination device 14, a rectangular reflection cover 13, a reflection sheet 15, and a light guide plate 16. The light guide plate 16 includes a light emitting surface 161, a light entering surface 162, and a bottom surface 163 parallel to the light emitting surface 161 and substantially perpendicular to the light entering surface 162. The reflection sheet 15 is arranged adjacent to the bottom surface 163 of the light guide plate 16. The illumination device 14 includes a light source 141, two wedges 142, a plurality of O-shaped rings 143, and an electric wire 144. The light source 141 is a cold cathode fluorescent lamp (CCFL) located adjacent to the light entering surface 162 of the light guide plate 16. Two end portions of the light source 141 are embedded in the wedges 142 respectively, and the rings 143 circle the wire 144 and the light source 141 and fix the electric wire 144 along the light source 141. The illumination device 14 is contained in the reflection cover 13. The frame 11 receives the reflection cover 13, the illumination device 14, the reflection sheet 15, and the light guide plate 16.
In assembly, firstly, the light source 141 and the electric wire 144 are both circled by the rings 143 so as to fix the wire 144 along with the light source 141. Secondly, the wedges 142 wedge two end portions of the light source 141 respectively, and then, the illumination device 14 is received in the cover 13. After that, the cover 13 and the illumination device 14 are located adjacent and opposite to the light entering surface 162, and the reflection sheet 15 is arranged at the bottom surface 163 of the light guide plate 16. Finally, the frame 11 receives the cover 13, the reflection sheet 15, and the light guide plate 16 therein.
In operation, part of the light beams emitted from the light source 141 enters the light guide plate 16 directly, and other part of them is reflected by the cover 13 before entering into the light guide plate 16 via the light entering surface 162. Light beams in the light guide plate 16 are guided to become a uniform plane light source and emitted out from the light emitting surface 161.
However, the cold cathode fluorescent lamp contains mercury which is harmful to environment. In addition, for the process of arranging the illumination device 14 in the cover 13 makes the assembly of the backlight module unduly burdensome.
Accordingly, what is needed is a backlight module configured to overcome the above-described problems.